Recent "special message" mass mailings by Mayor Marion Barry to city residents came under fire yesterday from several City Council members who peppered D.C. Budget Director Richard C. Siegel with questions about the messages during a briefing on the mayor's mid-year budget request.

The mailings, paid for with city funds, included a citywide message accompanying applications for the District's homestead exemption program and letters targeted to several city neighborhooods. They outlined the mayor's accomplishments and his plans for the future.

Council member Betty Ann Kane (D-At Large) said she was concerned that the messages appeared to have been mailed first class, rather than bulk mail. After the meeting, she said the letters were "clearly political."

Council Chairman David A. Clarke, in raising questions about the mailings, said he would be concerned if the letters were financed out of budgets other than the mayor's own. Council member Carol Schwartz (R-At Large), meanwhile, demanded a list of the mailings along with the source of funds for them.

Barry, responding later to reporters' questions, dismissed Kane's and other council members' concerns as "political, clearly political . . . . I don't need to use political mailings for my campaign. I am going to raise as much as I need anyway."

Barry, who on Saturday launched his campaign for a third term, told reporters that Kane had confided to him that she would like to be mayor but that she couldn't "muster the support."

Kane later disputed the account, confirming that she had told Barry she preferred to remain on the council but denying she made any references to a lack of support.

"It was just a financial consideration," she said of her decision not to run for mayor. Four years ago, Kane entered the mayoral stakes but then dropped out with a heavy campaign debt.

Somewhat overshadowed in the debate over the mailings was Barry's proposed mid-year revision of the city's $2.3 billion budget for fiscal 1986.

Siegel, answering questions and providing details on the spending plan, was on the receiving end of a blistering interrogation by Clarke, who questioned many of the budget officer's figures and criticized him for language in budget documents that referred to a new optical and dental plan for nonunion city employes.

Siegel, who was named D.C. budget director last month after previously serving as City Council budget director under Clarke, drew Clarke's wrath at the time for jumping to the mayor's camp. After yesterday's meeting, Siegel joked that he had expected the chairman's questions to be "hard but fair . . . Instead he was just hard."

Clarke took issue with a description of the benefits plan provided in budget documents, as having been a proposal of the mayor.

"You wrote it," Clarke said to Siegel, referring to the description. "You were here and know darn well it was a council program. I am very disappointed."

Siegel later acknowledged the error and attributed it to a misunderstanding by his staff.

Clarke, charging that the mayor's budget proposals do not reflect actual spending plans, produced charts showing that mid-year spending increases proposed for some agencies last year were never spent. "You have a lot of money to spend and you are not telling us where you are going to spend it," he said.

In discussing the mailings, Barry professed ignorance about the source of funds in an interview yesterday. However, an aide said the homestead exemption mailing was financed by the Department of Finance and Revenue and the targeted mailings were paid for by the mayor's Office of Community Services.

The mailings are allowable under District law, except during the 90-day period before the Sept. 9 Democratic primary, according to Keith Vance, director of the Office of Campaign Finance.

Barry promised yesterday he would comply with the law, but did not rule out any additional mailings before the 90-day deadline.